1. Field of the Invention
The present invention relates to a method of and apparatus for manufacturing a continuous slide fastener stringer including a stringer tape and a row of injection-molded coupling elements secured to the stringer tape along a longitudinal edge thereof.
2. Prior Art
U.S. Pat. No. 2,735,139, issued Feb. 21, 1956, discloses a method of securing a row of injection-molded coupling elements to a stringer tape by means of a pair of relatively movable mold halves having a plurality of mold cavities. In the method a plurality of openings are formed in the stringer tape along a longitudinal edge thereof and, substantially at the same time, melted (synthetic resin) material is injected into the mold cavities to form the coupling elements on the tape one at each of the openings. This requires that a plurality of piercing devices should be built in the mold, one at each of the mold cavities, making the mold extremely complicated. For this reason, the prior method has scarcely been available in practice for the production of a substantially endless or continuous slide fastener stringer.
Japanese Patent Publication (Tokkosho) Nos. 38-4771 and 53-28309 show respectively a method of and an apparatus for manufacturing a continuous slide fastener stringer including a continuous stringer tape and a row of injection-molded coupling elements secured to the stringer tape. However, this prior method and apparatus are not useful in that the stringer tape has a plurality of openings along the longitudinal edge thereof for preventing the coupling elements from being displaced on the tape. With such prior art it is difficult to form the individual coupling elements exactly at the corresponding openings.